JP3239147B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to a photoreceptor for electrophotography, which has a high coating quality even when the outermost layer is made of a highly durable coating formed by spray coating or nozzle coating. The present invention relates to a photoconductor for electrophotography in which abnormal image generation is suppressed.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic photoreceptor has been provided with a photoconductive layer mainly composed of selenium or a selenium alloy on a conductive support, and an inorganic photoconductive material such as zinc oxide or cadmium sulfide as a binder. Dispersed in poly-
Those using organic photoconductive materials such as N-vinyl carbazole and trinitrofluorenone or azo pigment, those using amorphous silicon, and the like are generally known.

In recent years, organic photoreceptors have been actively researched and developed due to reasons such as low raw materials and manufacturing costs, low environmental pollution, relatively free photoreceptor design, and high sensitivity. It is remarkable. One of the problems of the organic photoreceptor is high durability. Organic photoreceptors
Since the main raw material is organic matter, it is a-Si, As
When compared with inorganic photoconductors such as ₂ Se _3, the difference in the mechanical properties of the raw material itself, the surface hardness of the photosensitive member, it is difficult to say that sufficient in terms of printing durability, etc., there is still room for improvement.

However, recently, studies on increasing the durability of an organic photoreceptor and the like have revealed that, for example, a charge generation layer (CG)
L) and a charge transporting layer (CTL) are sequentially stacked.
A correlation was found between the degree of polymerization of the binder resin on the outermost surface of the photoreceptor and the printing durability of the photoreceptor. For example, by increasing the degree of polymerization of the binder resin in the TL, the printing durability was greatly improved. Thus, it has become desirable to employ a binder resin having a higher degree of polymerization for the outermost layer of the organic photoreceptor.

On the other hand, as a method of coating an organic photoreceptor,
Beat coat method, nozzle coat method, blade coat method,
There are a dipping method and a spray coating method. Among them, the spray coating method and the nozzle coating method require that the amount of liquid at the time of coating be small, that in the case of a laminated photoreceptor, that the lower layer coating does not stain the upper layer coating liquid, and that the solid content concentration of the coating liquid is low. Among the coating methods for organic photoreceptors, importance and necessity are considered from the viewpoints that the solvent selectable range is wide due to low temperature, coating is possible without interruption, and film thickness uniformity in the longitudinal direction is excellent. It is considered to be one of the highly reliable coating methods.

However, when the above-mentioned binder resin having a high degree of polymerization is formed into a film by this spray coating method, the coating quality becomes higher as the degree of polymerization of the binder resin becomes higher (that is, if higher durability is intended). It was found that the image deteriorated and an abnormal image such as shading unevenness was generated on the image. Analysis of the coating film quality at this time revealed that there were roughly two types of deterioration of the coating film quality. One was fine roughness with a pitch of 1 mm or less (high frequency roughness), and the other was One was large film thickness unevenness (roughness at low frequency) that appeared at a pitch of 3 to 10 cm. When examining the relationship between these roughness and image quality, high frequency roughness gives a halftone image roughness and uneven shading when the difference in height of adjacent irregularities exceeds 3 μm. Become. Further, it has been found that when the difference in the height of the concavo-convex portions exceeding 3 μm exceeds the roughness of the low frequency, a halftone image and a solid black image have different densities, and cannot be put to practical use.

As a result of further study, there is a trade-off relationship between the high frequency roughness and the low frequency roughness, and the greater the degree of polymerization of the binder resin, the more severe the trade-off relationship. The outermost layer containing a binder resin having a viscosity average molecular weight of 35,000 or more has low frequency roughness and high frequency roughness of 3 μm by the conventional spray coating method and nozzle coating method.
m or less, and it was found that a coating film quality and an image quality which can be used practically cannot be obtained. Therefore, there is a need for the development of the composition and formulation of the outermost layer capable of favorably forming the outermost layer containing a binder resin having a viscosity average molecular weight of 35,000 or more even when using the conventional spray coating method and nozzle coating method. I have.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned circumstances of the prior art. An object of the present invention is to provide a high-quality and highly durable electrophotographic photosensitive member in which an abnormal image based on high-frequency unevenness and low-frequency unevenness is suppressed. Another object of the present invention is to stabilize the electrical characteristics of the electrophotographic photosensitive member having high image quality and high durability.

[0009]

As a result of various studies, the present inventors have found that the heating conditions of the photoconductive material and other constituent materials of the photoreceptor are restricted from the viewpoint of physical or chemical stability. In the range of the allowable heating and drying conditions, the viscosity average molecular weight of the outermost layer resin and the solvent remaining in the outermost layer after the heating and drying, and the quality of the outermost layer coating film formed and the electrical properties are Have been found, and the present invention has been achieved.

That is, according to the present invention, in an electrophotographic photosensitive member having a photosensitive layer formed on a conductive support, the binder resin contained in the outermost layer of the photosensitive member has a viscosity average molecular weight of 3. At least one solvent having a boiling point of 135 ° C. or more is used in an amount of 100 to 10
000ppm contained in the outermost layer,
An electrophotographic photoreceptor characterized in that roughness and low-frequency roughness are 3 μm or less .

According to the present invention, the photoreceptor is characterized in that at least one solvent having a boiling point of 100 to 135 ° C. is contained in the outermost layer in an amount of 1,000 ppm or less based on the total amount of the photosensitive layer. An electrophotographic photoreceptor, characterized in that these photoreceptors further comprise at least one solvent having a boiling point of 50 to 100 ° C. in the outermost layer of 300 ppm or less based on the total amount of the photosensitive layer. A body is provided.

Hereinafter, the present invention will be described in more detail with reference to the drawings. 1 to 4 show examples of the configuration of a typical electrophotographic photosensitive member. In FIG. 1, a is a conductive support, b is a photoconductive layer, and FIG. 1 is a single-layer type electrophotographic photoreceptor having both functions of charge generation and charge transport in one layer. FIG. 2, FIG.
In FIG. 2, a represents a conductive support, c represents a charge transport layer, and d represents a charge generation layer. FIG. 2 shows a reverse type laminated electrophotographic photoreceptor, and FIG. 3 shows a normal layer type laminated electrophotographic photoreceptor. It is a photoconductor. In FIG. 4, a represents a conductive support, e represents a surface protective layer, f represents a photoconductive layer which may be a single-layer type or a laminated type, and FIG. 4 shows a photoconductive layer having a surface protective layer. It is a photoconductor for electrophotography. In addition, in FIGS. 1 to 4, an undercoat layer can be formed between the conductive support and the photoconductive layer as necessary.
It is also possible to form an intermediate layer between the photoconductive layer and the surface protective layer.

The outermost layer of the electrophotographic photosensitive member of the present invention is:
In FIG. 1, the single layer type photoconductive layer b is shown, and in FIG.
3, a charge transport layer c in FIG. 3, and a surface protective layer e in FIG. The preferred thickness of the outermost layer in FIGS. 1 to 4 is 10 to 10 with respect to the single-layer photoconductive layer in FIG.
30 μm, and 0.5 to 5 μm for the charge generation layer of FIG.
m, 10 to 30 μm for the charge transport layer in FIG.
Is 2 to 10 μm. The electrophotographic photoreceptor of the present invention can use the conventional configuration except for the outermost layer, and can take the configuration of FIGS. 1 to 4 described above, but achieves high durability, which is one of the objects of the present invention. To do so, the configurations of FIGS. 1, 3 and 4 are particularly preferred.

In the photoreceptor of the present invention, the outermost layer comprises a resin component having a viscosity average molecular weight of 35,000 or more, and at least one solvent having a boiling point of 135 ° C. or more, in an amount of 100 to 1 based on the total amount of the photosensitive layer.
The main feature is that it contains 0000 ppm. That is, the resin component constituting the outermost layer of the photoconductor of the present invention has a viscosity average molecular weight of 35,000 or more, and more preferably 50,000 or more from the viewpoint of abrasion resistance of the outermost layer. . This viscosity average molecular weight can be calculated from the following equation 1 by obtaining the intrinsic viscosity.

[1] [η] =KMw ^α  [Η]: intrinsic viscosity Mw: viscosity average molecular weight

The outermost layer of the photoreceptor of the present invention contains a solvent having a boiling point of 135 ° C. or more. Specific examples thereof include bromobenzene, o-dichlorobenzene, cyclohexanol, ethylene glycol and propylene glycol. Benzyl alcohol, diethylene glycol, diethylene glycol dimethyl ether, methyl carbitol, ethyl carbitol, cyclohexanone, N-methylformamide, N, N-dimethylformamide, triethyl phosphate, dimethyl sulfoxide, xylene, 2-
Ethoxyethanol and the like can be mentioned. When the viscosity average molecular weight of the resin constituting the outermost layer is 35,000 or more, these solvents contained in the outermost layer preferably have a range of 100 to 10,000 ppm from the viewpoint of the quality of the outermost layer coating film and the electrical properties. 2
The range of 00 to 6,000 ppm is particularly preferred.

Regarding the quality of the outermost layer coating film, when the content of the solvent having a boiling point of 135 ° C. with respect to the total amount of the photosensitive layer is less than 100 ppm, the above-described high-frequency roughness is easily generated, and an abnormal image such as halftone on the image can be generated. Nature, 20,
Above 000 ppm, low-frequency roughness increases, causing unevenness in density of black portions and halftone images due to uneven charging. Further, from the viewpoint of electrical characteristics, if the concentration is less than 50 ppm, the dark area potential is reduced by repeated use, and
If it exceeds 000 ppm, it is easy to cause a rise in the background potential by repeated use. In other words, the quality of the outermost layer coating film, the electrical characteristics, and the image over time from the initial stage have a boiling point of 135 ° C.
By setting the amount of the above solvent in the range of 100 to 10,000 ppm, a good level can be maintained.

Further, the outermost layer of the photoreceptor of the present invention has a boiling point of from 1,000 to 1,000 ppm based on the total amount of the photosensitive layer.
When a solvent at 35 ° C. is contained, the outermost layer having a higher viscosity (higher viscosity average molecular weight) can be formed while maintaining good coating film quality and electrical characteristics. Can achieve higher durability. Boiling point in this case 100
Specific examples of the solvent at -135 ° C include octane, toluene, 1,2-dibromoethane, tetrachloroethylene,
Examples thereof include chlorobenzene, 1-butanol, 2-methyl-1-propanol, 2-methoxyethanol, 1,4-dioxane, methyl isobutyl ketone, butyl acetate, and morpholine.

When the outermost layer of the photoreceptor of the present invention further contains a solvent having a boiling point of 50 to 100 ° C. of 300 ppm or less based on the total amount of the photosensitive layer, the coating quality and the electric properties are further improved. Thus, an electrophotographic photoconductor having high productivity can be obtained. Specific examples of the solvent having a boiling point of 50 to 100 ° C. in this case include carbon tetrachloride, hexane, cyclohexane, methanol, ethanol, diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane, acetone, methyl ethyl ketone, ethyl acetate, and trifluoroacetic acid. And the like.

In order to form the photoreceptor of the present invention, a resin component having a viscosity average molecular weight of 35,000 or more and other components constituting the outermost layer are mixed in the above-mentioned mixed solvent containing a solvent having a boiling point of 135 ° C. or more. After dissolving or dispersing, applying this by a coating method such as spraying or a nozzle, heating and drying may be performed.

In the present invention, for the conductive component other than the resin component and the high-boiling-point solvent in the outermost layer, the charge-generating substance, the charge-transporting substance, etc., exactly the same as the conventional ones can be used.

Hereinafter, the present invention will be described focusing on the case of the layer structure shown in FIG. 3, which is the most common embodiment of the organic photoreceptor.

As the conductive support, a conductor or an insulator subjected to a conductive treatment is used. For example, Al, Ni,
Metals such as Fe, Cu, Au and the like, metals such as Al, Ag, Au and the like or In ₂ O ₃ , on an insulating substrate such as polyester, polycarbonate, polyimide, glass, etc.
Examples thereof include those in which a thin film of a conductive material such as SnO ₂ is formed, paper subjected to a conductive treatment, and the like.

In the case of the layer structure shown in FIG. 3, the charge generation layer is made of a charge generation material or a charge generation material and a binder resin, and preferably has a thickness of 0.05 to 3 μm. In this case, as the charge generation material, for example, C.I. Pigment Blue 25 (color index CI 2118)
0), C.I. Pigment Red 41 (CI 2120)
0), CI Acid Red 52 (CI 4510
0), CI Basic Red 3 (CI4521)
0), an azo pigment having a carbazole skeleton (JP-A-53
95033), azo pigments having a distyrylbenzene skeleton (described in JP-A-53-133445), azo pigments having a triphenylamine skeleton (described in JP-A-53-132347), Azo pigments having a dibenzothiophene skeleton (JP-A-54-21728)
Azo pigment having an oxadiazole skeleton (described in JP-A-54-12742), an azo pigment having a fluorenone skeleton (described in JP-A-54-22834), and a bisstilbene skeleton. Pigments (described in JP-A-54-17733) and azo pigments having a distyryloxadiazole skeleton (JP-A-54-17733).
Azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-14967); phthalocyanine-based pigments such as C.I. Pigment Blue 16 (CI 74100); Brown 5 (CI 7341
0), indigo-based pigments such as sea bat die (CI 73030); Argol Scarlet 5 (manufactured by Bayer), Indus Scarlet R (manufactured by Bayer)
Such as perylene pigments, squirk dyes, hexagonal Se
And the like.

These charge generating materials are pulverized and dispersed together with a solvent such as tetrahydrofuran, cyclohexanone, dioxane or dichloroethane by a method such as a ball mill, an attritor or a sand mill. At this time, for example, polyamide, polyurethane, polyester, epoxy resin,
Resins such as polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinyl carbazole, and polyacrylamide may be added as a binder. The charge generation layer forming liquid thus adjusted is applied and dried by a method such as a bead coating method, a nozzle coating method, a blade coating method, a dipping method, and a spray method to form a charge generation layer.

The charge transport layer in the layer configuration shown in FIG. 3 is composed of a charge transport material and a binder resin. In this case, the charge transporting material is a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, in the main chain or side chain. Thiadiazole,
A compound having a nitrogen-containing cyclic compound such as triazole,
Triphenylamine compounds, hydrazone compounds (JP-A-55-46760), α-phenylstilbene compounds (JP-A-58-198043) and the like are used. These charge transporting materials are polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, and poly (vinyl acetate). Vinylidene chloride, polyarylate resin,
Phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-
Along with thermoplastic or thermosetting resins such as vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyl red resin, it is dissolved in solvents such as tetrahydrofuran, cyclohexanone, dioxane, and dichloroethane. The solution for forming the charge transport layer may be prepared by applying the solution, and the solution may be applied by a method such as a nozzle coating method or a spray coating method and dried.

In the present invention, it is necessary to leave a predetermined amount of a predetermined solvent in the outermost layer of the photosensitive layer. Therefore, when forming the charge transport layer in FIG. Is adjusted in advance, and the solid concentration of the forming solution, the mixing ratio of the mixed solvent, the coating conditions (for example, the distance between the gun and the support in spray coating) and the drying conditions are adjusted. Is formed.

[0027]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited thereto. All parts shown below are based on weight.

Examples 1 to 23 and Comparative Examples 1 to 17 Forty Al conductive supports having a size of 80 mmφ × 340 mm and a thickness of 3 mm were prepared, and the following charge generating layer forming liquid was sprayed on these conductive supports. It was applied to form a 0.1 μm thick charge generation layer.

(Preparation of Charge Generating Layer Forming Solution) 10.0 parts of a compound represented by the following structural formula 1, 2.5 parts of polyvinyl butyral resin (XYHL: manufactured by UCC) and 360 parts of tetrahydrofuran are placed in a ball mill for 72 hours. After kneading and dispersing, 211 parts of tetrahydrofuran and 356 parts of ethylene glycol monoethyl ether were further added, and the mixture was kneaded and dispersed for 1 hour, and then diluted with 376 parts of tetrahydrofuran and 664 parts of ethylene glycol monoethyl ether to prepare a liquid for forming a charge generation layer. did.

[0030]

Embedded image

Next, a charge transporting layer having a thickness of 20 μm was formed on the charge generating layer, and 40 photoreceptor samples for electrophotography having different amounts and kinds of solvents remaining in the charge transporting layer were obtained. The raw materials, conditions such as prescription, and the preparation procedure for forming the charge transport layer are shown below.

(Charge Transport Layer Forming Conditions)

Embedded image

Embedded image Solvent used: cyclohexanone (boiling point: 155.7 ° C.) xylene (boiling point: 140 ° C.) methyl isobutyl ketone (boiling point: 115.1 ° C.) toluene (boiling point: 110.6 ° C.) tetrahydrofuran (boiling point: 66.0 ° C.) acetone ( (Boiling point: 56.1 ° C.) Charge transfer material / binder resin = 1/1 Additive: silicone oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) Additive amount: 0.02% added to binder resin : Spray coating Heat drying time: 140 ° C, 40 minutes

(Preparation procedure) Under the conditions for forming the charge transport layer as described above, first, at least three solvents are selected from the above-mentioned solvents, and then the solvents are mixed at an appropriate ratio. The charge transport material and the binder resin are dissolved, additives are added, and the solvent type, the solid concentration, and the solvent mixing ratio are different.
No charge transport layer forming liquid was obtained, and this was spray-coated on the charge generation layer to form a charge transport layer. Table 1 shows the solvent ratio and solid content of each charge transport layer forming solution. In addition, in order to change the amount of the solvent in the charge transport layer, in addition to the formulation of the charge transport layer forming liquid, the temperature in the coating booth, the distance between the gun and the drum, and the like were also added as adjustment factors.

[0034]

[Table 1]

With respect to the forty electrophotographic photosensitive members obtained as described above, the content of the solvent having a boiling point of 135 ° C. or more in the charge transporting layer, based on the total amount of the photosensitive layer, and the boiling point of 100 to 13
The content of the solvent at 5 ° C and the content of the solvent having a boiling point of 50 to 100 ° C were analyzed, and the following evaluation was performed. ... High-frequency roughness of about 1 mm pitch on the electrophotographic photosensitive member surface and low-frequency unevenness (film thickness difference) of 5 to 10 cm pitch. ... The amount of change in dark area potential (Vd: initial setting -800 V) and light area potential (Vl: initial setting -100 V) from the initial stage to after copying 50,000 sheets in the copying machine (ΔV, respectively)
d, ΔVl). ... Abrasion film thickness of the charge transport layer after 50,000 sheet copy test. The above analysis results and evaluation results are shown in Tables 2-3 and Tables 4-6.
Shown in

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4] Note) Judgment: ×: Not practical △: Good without practical problems ○: Particularly good

[0039]

[Table 5] Note) Judgment: ×: Not practical △: Good without practical problems ○: Particularly good

[0040]

[Table 6] Note) Judgment: ×: Not practical △: Good without practical problems ○: Particularly good

From the above results, the following was confirmed. The higher the viscosity average molecular weight of the binder resin on the outermost surface of the photoreceptor, the higher the abrasion resistance in the copying machine. The higher the viscosity average molecular weight, the higher the surface roughness of the outermost layer,
The low-frequency roughness increases with each other, and there is a trade-off relationship between the high-frequency roughness and the low-frequency roughness. If the high-frequency roughness height of the outermost layer surface exceeds 3 μm, shading unevenness becomes remarkable in a halftone image and a solid black image, and there is a practical problem. When the low frequency roughness height of the outermost layer surface exceeds 3 μm, unevenness on a halftone image becomes conspicuous, and there is a practical problem. If the remaining amount of the solvent having a boiling point of 135 ° C. or more in the outermost layer is too small, high-frequency roughness occurs, and if it is too large, low-frequency roughness occurs, and there is a problem in image quality. If the amount of the solvent remaining in the outermost layer is too small, the black portion potential (Vd) decreases due to repeated use, and the electrostatic contrast decreases. If the amount of the solvent remaining in the outermost layer is too large, the light potential (Vl)
Gradually rises due to repeated use, causing soiling of the background,
Alternatively, the electrostatic contrast decreases.

In contrast, Embodiments 1 and 2 according to the present invention
Electrophotographic photoreceptor No. 3 contains a solvent having a boiling point of 135 ° C. or higher.
It is contained in the outermost layer in the range of 00 to 10,000 ppm, the high-frequency roughness and the low-frequency roughness are each reduced to 3 μm or less, the image from the beginning is good, and the dark area potential due to repeated use is low. There is little decrease and rise of bright part potential,
The decrease in contrast (ΔVd + ΔVl) is suppressed to about 100 V, and the durability is high. Furthermore, by including a solvent having a boiling point of 100 to 135 ° C in a concentration of 1,000 ppm or less and a solvent having a boiling point of 50 to 100 ° C in a concentration of 300 ppm or less, a better initial image and repetition quality can be obtained. Is suitable for forming a larger (more durable) outermost layer.

[0043]

According to the first aspect of the present invention, in the electrophotographic photoreceptor, the binder resin contained in the outermost layer has a viscosity average molecular weight of 35,000 or more and at least one solvent having a boiling point of 135 ° C. or more. 100 to 10,000 pp for the entire photosensitive layer
According to the present photoreceptor, an abnormal image due to coating film defects (high-frequency roughness and low-frequency roughness) is suppressed, and the repetition potential characteristics are stabilized. Therefore, a high-quality initial image and a repeated image can be obtained, and the durability of the photosensitive member is excellent.

The electrophotographic photoreceptor of claim 2 further comprises at least one solvent having a boiling point of 100 to 135 ° C. in the outermost layer of 1,000 ppm or less based on the total amount of the photosensitive layer. Since the outermost layer having high viscosity (high viscosity average molecular weight) can be formed, the durability is further improved.

The electrophotographic photoreceptor of claim 3 further comprises at least one solvent having a boiling point of 50 to 100 ° C. in the outermost layer of 300 ppm or less based on the total amount of the photosensitive layer. And the electrical characteristics are further improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a layer configuration of an electrophotographic photoconductor according to the present invention.

FIG. 2 is a schematic cross-sectional view showing another example of the layer configuration of the electrophotographic photosensitive member according to the present invention.

FIG. 3 is a schematic cross-sectional view showing another example of the layer configuration of the electrophotographic photoreceptor according to the present invention.

FIG. 4 is a schematic cross-sectional view showing another example of the layer configuration of the electrophotographic photoreceptor according to the present invention.

[Explanation of symbols]

 a conductive support b single-layer photoconductive layer c charge transport layer d charge generation layer e surface protective layer f photoconductive layer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Nakai 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-5-142793 (JP, A) JP-A Heisei JP-A-4-43363 (JP, A) JP-A-1-319752 (JP, A) JP-A-1-161244 (JP, A) JP-A-1-112249 (JP, A) JP-A-1-112248 (JP, A) A) JP-A-5-127395 (JP, A) JP-A-5-94029 (JP, A) JP-A-3-20768 (JP, A) JP-A-2-124576 (JP, A) JP-A-63 -261265 (JP, A) JP-A-2-67562 (JP, A) JP-A-4-320269 (JP, A) JP-A-4-368956 (JP, A) (58) Fields investigated (Int. . ^7, DB name) G03G 5/00

Claims (3)

(57) [Claims] 1. An electrophotographic photosensitive member comprising a photosensitive layer formed on a conductive support, wherein the binder resin contained in the outermost layer of the photosensitive member has a viscosity average molecular weight of 35,000 or more. At least one solvent having a boiling point of 135 ° C. or higher is contained in the outermost layer in an amount of 100 to 10,000 ppm based on the total amount of the photosensitive layer, and high-frequency roughness and low-frequency roughness on the surface of the outermost layer are reduced.
An electrophotographic photosensitive member having a thickness of 3 μm or less . 2. The electrophotographic photosensitive member according to claim 1, wherein at least one solvent having a boiling point of 100 to 135 ° C. is contained in the outermost layer in an amount of 1,000 ppm or less based on the total amount of the photosensitive layer. 3. An electrophotographic photoconductor according to claim 1, wherein at least one solvent having a boiling point of 50 to 100 ° C. is contained in the outermost layer in an amount of 300 ppm or less based on the total amount of the photosensitive layer.